Method for modulating light of photorefractive composition

Abstract

A method for forming a grating in a photorefractive composition comprising the steps of: providing a photorefractive composition containing a sensitizer and a polymer, wherein the polymer includes a first repeating unit which includes a moiety selected from the group consisting of the formulae (Ia), (Ib) and (Ic) as defined herein; and irradiating the photorefractive composition with a near infrared (NIR) laser, wherein the composition provides long grating holding time and the grating signal can be read out without external bias voltage.

1 . A method for forming a grating in a photorefractive composition, comprising:
 providing a photorefractive composition comprising a sensitizer and a polymer, wherein the polymer comprises a first repeating unit which includes a moiety selected from the group consisting of the following formulae (Ia), (Ib), and (Ic):   
     
       
         
         
             
             
         
       
       wherein each Q in formulae (Ia), (Ib) and (Ic) independently represents an alkylene or a heteroalkylene; Ra 1 -Ra 8 , Rb 1 -Rb 27 , and Rc 1 -Rc 14  in formulae (Ia), (Ib), and (Ic) are each independently selected from the group consisting of hydrogen, linear or branched optionally substituted C 1 -C 10  alkyl or heteroalkyl, and optionally substituted C 6 -C 10  aryl; and 
       irradiating the photorefractive composition with a near infrared (NIR) laser to form a grating, wherein the composition is formulated to provide a grating holding time of about one hour or more upon irradiation by the NIR laser. 
     
   
   
       2 . The method of  claim 1 , wherein the NIR laser has a wavelength of about 980 nm. 
   
   
       3 . The method of  claim 1 , wherein the photorefractive composition has a transmittance greater than about 30% at a thickness of about 105 μm when irradiated by the NIR laser. 
   
   
       4 . The method of  claim 1 , wherein a grating signal of the photorefractive composition formed by irradiation by the NIR laser can be read out without applying external bias voltage. 
   
   
       5 . The method of  claim 1 , wherein the photorefractive composition further comprises a plasticizer. 
   
   
       6 . The method of  claim 1 , wherein the photorefractive composition further comprises a chromophore. 
   
   
       7 . The method of  claim 1 , wherein the sensitizer comprises a molecule according to formula (V): 
     
       
         
         
             
             
         
       
       wherein Re 1 -Re 8  and Rg 1 -Rg 5  in formula (V) are each independently selected from the group consisting of hydrogen, linear or branched C 1 -C 10  alkyl or heteroalkyl, C 6 -C 10  aryl, and halogen; and Rf 1  and Rf 2  are each independently selected from the group consisting of hydrogen and linear or branched optionally substituted C 1 -C 10  alkyl. 
     
   
   
       8 . The method of  claim 7 , wherein Re 1 -Re 8  and Rg 1 -Rg 5  are each independently selected from the group consisting of hydrogen and linear or branched C 1 -C 4  alkyl or heteroalkyl; and Rf 1  and Rf 2  are each independently selected from the group of linear or branched C 1 -C 10  alkyl, —CH 2 CH 2 OH, —CH 2 CH 2 OCOCH 3 , and —CH 2 CH 2 OSi(CH 3 ) 2 C(CH 3 ) 3 . 
   
   
       9 . The method of  claim 7 , wherein the sensitizer comprises 2-[2-{5-[4-(di-n-butylamino)phenyl]-2,4-pentadienylidene-1,1-dioxido-1-benzothien-3(2H)-ylidene]malononitrile. 
   
   
       10 . The method of  claim 1 , wherein the sensitizer is provided in the composition in an amount in the range of about 0.1% to about 10% based on the weight of the photorefractive composition. 
   
   
       11 . The method of  claim 1 , wherein the sensitizer is provided in the photorefractive composition in an amount in the range of about 0.5% to about 5% based on the weight of the photorefractive composition. 
   
   
       12 . A composition configured to be photorefractive upon irradiation by a near infrared (NIR) laser comprising a sensitizer and a polymer, wherein the polymer comprises a first repeating unit which includes at least one moiety selected from the group consisting of the following formulae (Ia), (Ib) and (Ic): 
     
       
         
         
             
             
         
       
       wherein each Q in formulae (Ia), (Ib) and (Ic) independently represents an alkylene group or a heteroalkylene group; Ra 1 -Ra 8 , Rb 1 -Rb 27  and Rc 1 -Rc 14  in formulae (Ia), (Ib), and (Ic) are each independently selected from the group consisting of hydrogen, linear or branched optionally substituted C 1 -C 10  alkyl or heteroalkyl, and optionally substituted C 6 -C 10  aryl; and 
       wherein the composition provides a grating holding time of about one hour or more upon irradiation by the NIR laser. 
     
   
   
       13 . The composition of  claim 12 , wherein the photorefractive composition is formulated such that a grating that is irradiated into the photorefractive composition can be read out of the photorefractive composition without applying an external bias voltage. 
   
   
       14 . The composition of  claim 12 , wherein the polymer further comprises a second repeating unit which includes a moiety represented by the following formula (IIa): 
     
       
         
         
             
             
         
       
       wherein Q in formula (IIa) represents an alkylene group or a heteroalkylene group; R 1  in formula (IIa) is selected from the group consisting of hydrogen, linear C 1 -C 10  alkyl, branched C 1 -C 10  alkyl and C 6 -C 10  aryl; G in formula (IIa) is a π-conjugated group; and Eacpt in formula (IIa) is an electron acceptor group. 
     
   
   
       15 . The composition of  claim 14 , wherein the second repeating unit is represented by the following formula (IIa′): 
     
       
         
         
             
             
         
       
       wherein Q in formula (IIa′) represents an alkylene group or a heteroalkylene group; R 1  in formula (IIa′) is selected from the group consisting of hydrogen, linear C 1 -C 10  alkyl, branched C 1 -C 10  alkyl, and C 6 -C 10  aryl; G in formula (IIa′) is a π-conjugated group; and Eacpt in formula (IIa′) is an electron acceptor group. 
     
   
   
       16 . The composition of  claim 14 , wherein G in formula (IIa) is represented by a structure selected from the group consisting of the following formulae (G-1) and (G-2): 
     
       
         
         
             
             
         
       
       wherein Rd 1 -Rd 4  in formulae (G-1) and (G-2) are each independently selected from the group consisting of hydrogen, linear C 1 -C 10  alkyl, branched C 1 -C 10  alkyl, C 6 -C 10  aryl, and halogen; and R 2  in formulae (G-1) and (G-2) is independently selected from the group consisting of hydrogen, linear C 1 -C 10  alkyl, branched C 1 -C 10  alkyl, and C 6 -C 10  aryl. 
     
   
   
       17 . The composition of  claim 14 , wherein Eacpt in formula (IIa) is represented by oxygen or a structure selected from the group consisting of the following formulae (E-2) to (E-6): 
     
       
         
         
             
             
         
       
       wherein R 5 , R 6 , R 7  and R 8  in formulae (E-3), (E-4), and (E-6) are each independently selected from the group consisting of hydrogen, linear C 1 -C 10  alkyl, branched C 1 -C 10  alkyl, and C 6 -C 10  aryl. 
     
   
   
       18 . The composition of  claim 12 , wherein the composition further comprises a plasticizer. 
   
   
       19 . The composition of  claim 12 , wherein the composition further comprises a chromophore. 
   
   
       20 . The composition of  claim 12 , wherein the sensitizer comprises a molecule according to formula (V): 
     
       
         
         
             
             
         
       
       wherein Re 1 -Re 8  and Rg 1 -Rg 5  in formula (V) are each independently selected from the group consisting of hydrogen, linear or branched C 1 -C 10  alkyl or heteroalkyl, C 6 -C 10  aryl, and halogen; and Rf 1  and Rf 2  are each independently selected from the group consisting of hydrogen, linear or branched optionally substituted C 1 -C 10  alkyl. 
     
   
   
       21 . The composition of  claim 20 , wherein Re 1 -Re 8  and Rg 1 -Rg 5  are each independently selected from the group consisting of hydrogen and linear or branched C 1 -C 4  alkyl; and Rf 1  and Rf 2  are each independently selected from the group of linear or branched C 1 -C 10  alkyl, CH 2 CH 2 OH, CH 2 CH 2 OCOCH 3 , and CH 2 CH 2 OSi(CH 3 ) 2 C(CH 3 ) 3 . 
   
   
       22 . The composition of  claim 20 , wherein the sensitizer comprises 2-[2-{5-[4-(di-n-butylamino)phenyl]-2,4-pentadienylidene-1,1-dioxido-1-benzothien-3 (2H)-ylidene]malononitrile. 
   
   
       23 . The composition of  claim 12 , wherein the sensitizer is provided in the composition in an amount in the range of about 0.1% to about 10% based on the weight of the composition. 
   
   
       24 . The composition of  claim 12 , wherein the sensitizer is provided in the composition in an amount in the range of about 0.5% to about 5% based on the weight of the composition. 
   
   
       25 . The composition of  claim 12 , wherein the first repeating unit selected from the group consisting of the following formulae (Ia′), (Ib′) and (Ic′): 
     
       
         
         
             
             
         
       
       wherein each Q in formulae (Ia′), (Ib′) and (Ic′) independently represents an alkylene group or a heteroalkylene group; Ra 1 -Ra 8 , Rb 1 -Rb 27  and Rc 1 -Rc 14  in formulae (Ia′), (Ib′) and (Ic′) are each independently selected from the group consisting of hydrogen, linear or branched optionally substituted C 1 -C 10  alkyl or heteroalkyl, and optionally substituted C 6 -C 10  aryl. 
     
   
   
       26 . The composition of  claim 12 , wherein the composition has a transmittance greater than about 30% at a thickness of about 105 μm when irradiated by the NIR laser. 
   
   
       27 . The composition of  claim 12 , wherein the composition is configured to be photorefractive upon irradiation by the NIR laser at a wavelength of about 980 nm. 
   
   
       28 . An optical device comprising the composition of  claim 12 .